In roller mills of the known type the material for grinding which is to be comminuted under high pressure in the roller gap is delivered to this roller gap from above with the aid of a material inlet shaft. The material inlet shaft is generally rectangular in cross-section and has two end walls which are associated with the two opposing roller end walls to ensure that the roller gap formed by the grinding rollers is covered as closely as possible at the ends.
Because of the relatively high speed at which the material for grinding is drawn in and the high grinding pressure which is exerted on the material in the region of the grinding gap, the corresponding regions of the shaft end walls are subject to relatively high wear stresses. For this reason each shaft end wall has a releasably fixed carrier plate on which a plate-shaped wear part which covers the wedge region of the grinding gap at the end and is made from suitable wearing material, especially sintered metal, is provided so that a sort of wear-resistant armouring is produced in these wedge regions. For the construction of these wear parts not only have various wearing materials been tried out but also a plurality of means for fixing these wear parts on the carrier plate. The latter is important so that used wear parts can be replaced simply and quickly. In the past plates having a sufficiently large area, especially sintered metal plates, were generally used as wear parts. However, it was repeatedly shown that plates which are stuck on fall out and plates which are soldered on are broken away; even costly clamping of sintered metal plates by means of dovetail joints frequently leads to fractures.
Apart from these disadvantages as regards the fixing it is generally necessary to throw away the plates which are frequently only partly worn or broken off and replace them by new plates.
The object of the invention, therefore, in a roller mill is to construct particularly the material inlet shaft with its end walls and the carrier plates supported thereon with the plate-shaped wear parts in such a way that with relatively simple design and quick and economical way of replacing simple plate-shaped wear parts and an extremely reliable fixing of these wear parts on the appertaining carrier plates is ensured.